Natural gas is often available in areas remote from where it will be ultimately used. When carrying it, natural gas is cooled to a temperature of approximately −260° F. (−160° C.) at atmospheric pressure so that it condenses to a liquid called liquefied natural gas (LNG). This LNG is normally transported overseas in appropriate carrier vessels.
Numerous process cycles have been developed for LNG production to provide the large refrigeration requirements. Such cycles typically use a mixed refrigerant comprising light hydrocarbons and optionally nitrogen. e.g., U.S. Pat. No. 4,274,849 patent discloses a mixture of hydrocarbons, at least two, as a refrigerating fluid in a process to liquefy a natural gas.